陆地棉×比克氏棉F1细胞学观察及育性恢复的研究

STUDIES ON CHROMOSOME BEHAVIOUR OF F1 AND FERTILITY RESTORATION IN HYBRID OF GOSSYPIUM HIRSUTUM×G.BICKⅡ

通过对杂交铃滴GA_3和NAA及胚培养,1982年获得陆地棉(Gossypium hirsutum)×比克氏棉(G.bickii)F_1一株,雌雄不育。中期Ⅰ染色体构型为33.24Ⅰ+2.67Ⅱ+0.095Ⅲ+0.048Ⅳ。二价体平均交叉数1.23。后期Ⅰ染色体分向两极不同步,数目也不均等,在大多数细胞中,染色体自由散布,不形成明确的赤道板;后期Ⅱ出现各种畸形孢子群,由此产生畸形不育花粉粒。F_1枝条嫁接到陆地棉上并给予凉夜短日条件,雌性恢复了低育性,可回交结籽。至BC_3育性恢复正常。到1988年已得到一批兼有陆地棉的株型、白绒、早熟及结铃性,和比克氏棉的红花具紫斑、强纤维等特性的稳定选系。比克氏棉特性首次向陆地棉转育成功。

By means of dripping GA_3(50 ppm) and NAA(40 ppm) on the hybrid boll-embryo culture in vitro,one F_1 plant of G.hirsutum × G.bickii was obtained in 1982,the F_1 plant flowered profusely but failed to produce any seeds when selfed or back crossed.In meiosis of the pollen mother cell (PMC),mean chromosome conjugation was 33.24 Ⅰ +2.67 Ⅱ +0.095 Ⅲ + 0.048 Ⅳ with high frequence (77.6%) of one chiasma attenuated bivalents.Mean number of chiasmta per bivalents was 1.23.The univalents were scattered over the achromatic figure for most PMCs.Although a few of the bivalents were located in the equatorial region,but they did not form a definite plate.At the second anaphase the distribution of chromosomes was- ??very irregular.In the majority of cases,multipolar distripution of chromosomes was observed. At the completion of meiosis highly abnormal sporads occurred,which contained from 2 to 13 spores of various sizes.Thus,all of the pollen grains produced were sterile.When the F_1 branches were grafted onto the upland cotton and thence they were backcrossed under short -day (12 hours) and cold night(15—18℃) exposure,BC_1 seeds could be harvested.BC_1 and BC_2 plants could grow up later.In the BC_3 generation,the fertility of the hybrid was restored.By 1988,ten pure lines of hybrid with the characers of both male parent (viz.red petal with purple spot and strong fibre) and female parent (white fibre,high yield,earliness ect.) were selected for the first time.